Organometallic chemical vapor deposition of high <i>T</i>
                  <i>c</i> superconducting films using a volatile, fluorocarbon-based precursor

Zhao, Jing; Dahmen, K. H.; Marcy, Henry O.; Tonge, L. M.; Marks, Tobin J.; Wessels, Bruce W.; Kannewurf, Carl R.

doi:10.1063/1.100473

Cited by 110 publications

(26 citation statements)

References 21 publications

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“…When this technique is combined with mass spectrometry, analytical methods, based upon the use of isotopic tracers, can be devised for metals. Recently, metal P-diketonates were used as precursors for chemical vapor deposition (2)(3)(4), a promising technique for the preparation of thin films of high T, superconducting oxides (5), and the application of mass spectrometry to characterize the alkaline earth complexes for this purpose has been described (6).…”

Section: Introductionmentioning

confidence: 99%

Electron ionization mass spectrometry of cobalt(III) β-diketonates and monothio-β-diketonates possessing aryl and fluorinated alkyl substituents

Reimer¹,

Westmore²,

Das³

1992

Can. J. Chem.

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. Can. J. Chem. 70, 952 (1992).Electron ionization positive ion mass spectra of 15 substituted cobalt(II1) P-diketonates and monothio-P-diketonates, CO"'L,, where L = RCXCHCOR', R = phenyl, 2-thienyl, or 2-naphthyl; X = 0 or S; and R' = CHF2, CF,, C2FS, or n-C,F,, show a marked dependence on the ligand. Molecular ions, [CO"'L,]+', are observed only for some of the more highly fluorinated complexes (R' = C2FS or n-C3F7). The [Co1"L2] '' ion, possibly generated by ionization of CO"L forme! by thermal degradation, or by electron ionization of Col''L,, typically decomposes by elimination of a radical, i.e., L or R' , to yield ions containing Co(I1); subsequent decompositions proceed preferentially by loss of even-electron neutral species, also to yield ions containing Co(l1). Cobalt-containing ions in which fluorine has rearranged to the metal decrease in variety and abundance for the ligands with higher fluorine content. When metal-bonded oxygen is replaced by sulfur, fluorine migration to Co(III), rather than to Co(II), is preferred. These trends are consistent with a combination of several different concepts including the ability of the metal to undergo valency change, the principle of Hard and Soft Acids and Bases, and the inductive capabilities of the ligand donor atoms and of the R and R' groups. Ion decomposition pathways are proposed.Key words: mass spectrometry, cobalt complexes, P-diketonates, fluorinated chelate complexes. Mots clts : spectrometric de masse, complexes du cobalt, P-dicktonates, complexes de chelates fluorCs.[Traduit par la redaction] Introduction The significant volatility and stability of metal P-diketonates and their derivatives make them suitable for gas chromatography (1). When this technique is combined with mass spectrometry, analytical methods, based upon the use of isotopic tracers, can be devised for metals. Recently, metal P-diketonates were used as precursors for chemical vapor deposition (2-4), a promising technique for the preparation of thin films of high T, superconducting oxides (5), and the application of mass spectrometry to characterize the alkaline earth complexes for this purpose has been described (6).The mass spectra of these complexes are of interest in their own right because their wide variety permits assessment of the influence exerted by bonding and structure factors, i.e., (i) the central metal atom, (ii) the ligand donor atoms, and

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Section: Introductionmentioning

confidence: 99%

Electron ionization mass spectrometry of cobalt(III) β-diketonates and monothio-β-diketonates possessing aryl and fluorinated alkyl substituents

Reimer¹,

Westmore²,

Das³

1992

Can. J. Chem.

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“…As we shall see, this is a feature often observed whenever organofluorine ligands come in contact with electropositive metal ions. It may not be a coincidence that such fluorinated metal complexes usually deposit metal fluorides when used as CVD precursors, although alkali metal fluorides are thermodynamically stable and might be expected to form in any case (9,10).…”

Section: Alkali and Alkaline Earth Derivativesmentioning

confidence: 97%

Recent Developments in the Chemistry of Fluorinated Isopropoxides and Tertiary Butoxides

Purdy

George

1994

ACS Symposium Series

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Studies on OCH(CF 3 ) 2 , OCMe(CF3) 2 , OCMe 2 (CF 3 ), and OC(CF3)3 derivatives of the alkali metals, alkaline earth metals, transition metals, and the lanthanide elements are reviewed, with emphasis on work reported since 1988. Alkali and alkaline earth fluoroalkoxides are generally made from reaction between the alcohol and the metal, its hydride, or organometallics. Most syntheses of transition metal derivatives involve reaction between metal halides and alkali or alkaline earth salts, or the alcoholysis of metal alkyls, alkoxides and amides. Coordination between organic fluorine and electropositive metals (ie. Na, Ba, Τl, Pr) is often observed in the crystal structures of these fluoroalkoxides and may be related to their use as chemical vapor deposition precursors for metal fluorides.Fluorinated metal alkoxides are of interest for a number of reasons. Complexes with bulky fluorinated alkoxy ligands usually have substantially greater volatility and solubility than their unfluorinated counterparts, primarily as a result of low polarizability of the C-F bond(7,2). In addition, the high electronegativity of Rp reduces the basicity of the alkoxy oxygen, which renders extended alkoxy bridged polymers less favorable than those with unfluorinated alkoxy groups (2). These properties are of interest in the design of new precursors for CVD (chemical vapor deposition) and sol-gel types of ceramic synthesis. Of note here is the ability of fluorinated metal complexes to serve as precursors for metal fluorides (3). The high electronegativity and oxidation resistance of fluorinated alkoxy groups can help to stabilize the higher oxidation states of some metals and also finds application in the design of new olefin metathesis catalysts.Although many types of fluoro-alkoxy ligands are known, this chapter is primarily concerned with the alkoxy derivatives of 1,1,1,3,3,3-hexafluoroisopropanol (HOCH(CF3)2, H[HFIP]), 1,1,1-trifluoro-im-butanol (HOCMe2CF3, HfTFTB]) 1,1,1,3,3,3-hexafluoro-fô/t-butanol (HOCMe(CF3)2, HfHFTB]), and perfluoro-terf-butanol (HOC(CF3)3, H[PFTB]). Emphasis is placed on compounds reported after 1988, as an excellent review by Willis details work prior to that time (2). Discussion will focus on the synthesis of these This chapter not subject to U.S.

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“…Metal complexes of dipivaloylmethanate (Hdpm) and heptafluoromethyloctanedionate (Hfod) are the most frequently used initial components [2,3]. However, despite all the successes in the production of superconducting films from metal [~-diketonates, questions concerning the thermal stability of these compounds in various states of aggregation remain practically uninvestigated.…”

Section: Introductionmentioning

confidence: 99%

Mass spectrometric study of thermal stability of copper(II) bis(dipivaloylmethanate) vapour

Bykov

Semyannikov

Игуменов

1992

Journal of Thermal Analysis

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The processes of thermal destruction of copper(II) bis(dipivaloylmethanate) (Cu(dpm)2) in the temperature range 150~176were studied by using a two-temperature variant of a double chamber Knudsen cell, with mass spectrometric recording of the gas-phase composition. The temperature range of stability of the vapour of the complex in vacuum was determined, as were those of its mixtures with oxygen in different proportions. The temperature dependence of the rate constant of the thermolysis of (Cu(dpm)2) vapour was obtained. The thermal stability of Hdpm vapour and the influence of oxygen on the thermolysis of the ligand were studied.

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Organometallic chemical vapor deposition of high T c superconducting films using a volatile, fluorocarbon-based precursor

Cited by 110 publications

References 21 publications

Electron ionization mass spectrometry of cobalt(III) β-diketonates and monothio-β-diketonates possessing aryl and fluorinated alkyl substituents

Electron ionization mass spectrometry of cobalt(III) β-diketonates and monothio-β-diketonates possessing aryl and fluorinated alkyl substituents

Recent Developments in the Chemistry of Fluorinated Isopropoxides and Tertiary Butoxides

Mass spectrometric study of thermal stability of copper(II) bis(dipivaloylmethanate) vapour

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